Editing Post-Carboniferous burial and exhumation histories of Carboniferous rocks of the southern North Sea and adjacent onshore UK

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Thermal-history solutions derived from the AFTA data in samples from the well are summarized in [[:File:YGS_CHR_03_POST_TAB_02.jpg|Table 2]], which also summarizes estimates of maximum palaeotemperature derived from VR data from the Jurassic section in this well. If we assume that results from this well represent the effects of a synchronous cooling episode, estimates of the onset of cooling from AFTA in the five samples suggest that cooling from maximum palaeotemperatures began some time between 90 Ma and 40 Ma. The detail of the track-length data in these samples also suggests a possible later cooling episode from a lower palaeothermal peak. This most likely represents the Neogene cooling identified from AFTA onshore (Green et al. 2001) and also suggested by Japsen (1997). However, the detail of the Cainozoic cooling history is beyond the scope of this contribution and is not pursued here.
 
Thermal-history solutions derived from the AFTA data in samples from the well are summarized in [[:File:YGS_CHR_03_POST_TAB_02.jpg|Table 2]], which also summarizes estimates of maximum palaeotemperature derived from VR data from the Jurassic section in this well. If we assume that results from this well represent the effects of a synchronous cooling episode, estimates of the onset of cooling from AFTA in the five samples suggest that cooling from maximum palaeotemperatures began some time between 90 Ma and 40 Ma. The detail of the track-length data in these samples also suggests a possible later cooling episode from a lower palaeothermal peak. This most likely represents the Neogene cooling identified from AFTA onshore (Green et al. 2001) and also suggested by Japsen (1997). However, the detail of the Cainozoic cooling history is beyond the scope of this contribution and is not pursued here.
  
Cooling beginning between 90 Ma and 40 Ma is consistent with the Palaeocene cooling identified in AFTA data from onshore wells and outcrop data (reviewed earlier), and the simplest interpretation of these data is that results from the 47/25-1 well also represent the effects of a regional cooling episode that began in the interval 65–55 Ma. Although it is true that, at the limits of the data, cooling in the 47/25-1 well may have begun at any time between 90 Ma and 40 Ma, synthesis of unpublished results from other offshore wells in the vicinity of this well also provide a tighter timing constraint to the interval 65–55 Ma for the onset of cooling. Therefore, it seems beyond reasonable doubt that the preserved sedimentary units in the offshore EMS, as well as the onshore, have undergone major cooling through Cainozoic times, beginning at about 60 Ma.
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Cooling beginning between 90Ma and 40 Ma is consistent with the Palaeocene cooling identified in AFTA data from onshore wells and outcrop data (reviewed earlier), and the simplest interpretation of these data is that results from the 47/25-1 well also represent the effects of a regional cooling episode that began in the interval 65–55Ma. Although it is true that, at the limits of the data, cooling in the 47/25-1 well may have begun at any time between 90Ma and 40Ma, synthesis of unpublished results from other offshore wells in the vicinity of this well also provide a tighter timing constraint to the interval 65–55Ma for the onset of cooling. Therefore, it seems beyond reasonable doubt that the preserved sedimentary units in the offshore EMS, as well as the onshore, have undergone major cooling through Cainozoic times, beginning at about 60Ma.
  
 
Estimates of maximum palaeotemperature derived from AFTA and VR data in the 47/25-1 well are plotted against depth (from KB) in [[:File:YGS_CHR_03_POST_FIG_04.jpg|Figure 4]]. The values derived from VR show some scatter, but overall are consistent with the palaeotemperatures indicated by the AFTA data. One value appears to be much lower than the majority, which we interpret as representing suppression of the reflectance level in this sample, similar to the Edale Shales from outcrop, discussed earlier. Omitting this lower VR value, the combined palaeotemperature constraints from AFTA and VR define a linear palaeotemperature profile, subparallel to the present-day temperature profile (also shown in [[:File:YGS_CHR_03_POST_FIG_04.jpg|Figure 4]]) but offset to higher values by a difference of about 40°C.
 
Estimates of maximum palaeotemperature derived from AFTA and VR data in the 47/25-1 well are plotted against depth (from KB) in [[:File:YGS_CHR_03_POST_FIG_04.jpg|Figure 4]]. The values derived from VR show some scatter, but overall are consistent with the palaeotemperatures indicated by the AFTA data. One value appears to be much lower than the majority, which we interpret as representing suppression of the reflectance level in this sample, similar to the Edale Shales from outcrop, discussed earlier. Omitting this lower VR value, the combined palaeotemperature constraints from AFTA and VR define a linear palaeotemperature profile, subparallel to the present-day temperature profile (also shown in [[:File:YGS_CHR_03_POST_FIG_04.jpg|Figure 4]]) but offset to higher values by a difference of about 40°C.

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